The distribution of the light emitting angles of light beams from a conventional light guide plate is broad. In a convention light guide module, the light guide plate is collocated and is used in conjunction with an optical film for guiding the light beams to a normal viewing direction. Currently, the most commonly known light source module is configured with a light guide plate having dots, a light emitting device disposed at a side of the light guide plate, a diffuser and two prism films disposed on the light guide plate, and a reflection sheet disposed under the light guide plate. However, the light emitting angle of light beams from a light source module with such a configuration is distributed at a broader range, regardless it is in the horizontal direction or the vertical direction. Hence, the brightness of this type of light source module is lower at the normal viewing direction.
In Taiwan patent application publication No. 201030376, an optical signal, after passing through a reflective device, a collimator and a guiding device to form a collimated optical signal, is disclosed. In Taiwan patent application publication No. 200933556, a display apparatus including a display device, a turning film, a second light guide device, a turning mirror and a light source is disclosed. In U.S. Pat. No. 7,239,792, a light, emitted from a backlight module, guided to and emitted out from a light emitting surface of a main light guide plate after passing through a sub light guide plate and a second optical fiber, is disclosed. In Taiwan patent application publication No. 200639518, an illumination system including a plurality of optical collimation regions and light mixing regions is disclosed. In U.S. Pat. No. 5,757,557, a secondary lens including a front-facing cavity and an internal cavity is disclosed. In the Taiwan patent No. 1284235, a light guide plate having a light incident surface facing the light source, and the light guide plate having a protruded ball-shape surface facing the light source is disclosed. In Taiwan patent No. M311911, a light guide plate having a V-shaped ridge at the bottom surface and the light emitting surface is disclosed.